This Sigma 55-200mm f/4-5.6 DC HSM Lens now incorporates the HSM feature, which gives this lens the capability to auto focus with all Nikon DSLR cameras (including the D40 and D40x). In addition, with the HSM (Hyper Sonic Motor) incorporated into this lens, focusing will be quieter and more responsive.
The 55-200mm f/4.5-5.6 DC lens was exclusively designed to suit the characteristics of digital SLR cameras. Ideal as a full-range telephoto zoom lens, this compact telephoto zoom lens provides an equivalent range of approx. 88-320mm when used with a Nikon digital SLR camera (*).
DC lenses are exclusively designed for digital SLR cameras. The image circle (rear of lens) is made to match the smaller dimensions used for the image sensor on digital cameras. As a result, these lenses are also more compact and lightweight, and are better matched to digital SLR cameras.
(*) Note: Not suitable for 35mm film SLR cameras, or for 35mm size "full-frame" digital cameras, e.g. D3 or Kodak Pro SLR/n.